Thermostat.



(No Model.) Y

M4-9@ lNVEN-rm RICHARD P. OSGOOD AND JOHN D. OSGOOD, OF METIIUEN,MASSACHUSETTS.

THERMOSTAT.

SPECIFICAT] ON forming part of Letters Patent No. 640,40*?, datedJanuary 2, 1900.

Application filed June 5, 1899. Serial No. 719,370. (No model.)

To @ZZ wiz/0m il? may con/cern:

Be it known that we, RICHARD P. OsG-OOD and JOHN D. OsGOOD, citizens ofthe United States, residing in Methuen, in the county of Essex and Stateof Massachusetts, have invented new and useful Improvements inThermostats, of which the following is a specification.

This invention relates to that class of thermostats in which a closedelectrical circuit is open ed by the dropping by gravity of a weightedarm which is released by the melting of a fusible solder; and theinvention consists in the novel construction and arrangement of partshereinafter described, and illustrated in the accompanying drawings, inwhich- Figure l is a perspective view of our thermostat suitably incasedand adapted to be supported from the ceiling of a room. Fig. 2 is acentral longitudinal vertical section of the saine. Fig. 3 is a plan ofthe under side with the case removed. Fig. 4 is a cross vertical sectiontaken on line 4, Fig. 2. Fig. 5 is a cross vertical section taken online 5, Fig. 2.

Similar letters of reference indicate corresponding parts.

A represents a non-conductive plate or bed adapted to be screwed to aceiling S through the holes c by means of screws d.

B B/ are the electrodes, protected by insulation Z) and connecting withthe electric wires e.

C is a metallic spring secured to the under side of the plate A by meansof a metallic bolt or screw D, which extends up through the plate A andmakes contact with the electrode l5'.

E is a horizontally-arranged metallic arm or bar supporting a weight Fand provided at one end with a ledge or step E', on which the free endof the spring C normally bears. The opposite end of the bar E is unitedby fusible solder E" with the downwardly-extending portion H of a plateconsisting of two wings H, secured to the under surface of the plateorbed A. This plate His connected by a metallic screw D' with theelectrode B. The bed A is recessed on its under side at A to accommodatethe weight F. A case K incloses the above-named parts and is securedtothe side edges of the plate or bed A by means of the inwardly-bentportions K', which press into corresponding grooves in the edge of thebed.

In the different figures of the drawings the parts are in their normalpositions, the circuit being closed and completed through the post orscrew D, plate H H', solder E", bar E, spring` C, and post or screw D.yThen the temperature rises sufficiently to melt the solder E, the bar Eis released and the weight F accelerates its fall, thus breaking thecircuit.

It will be noticed that in this contrivance he bar does not draw awaylaterally from the portion H of the plate, but drops on a plane which isparallel with the plate H'. Hence it drops easily and quickly, thesoftened solder constituting a sort of hinge, so that it swings down,the weight F striking the floor of the case first.

The spring C serves not only for an electrical connection, but also toabsorb vibration.

lt is found iu practice that it is advisable to have the case air-tight,although this is not absolutely essential to the operation of thedevice.

Having thus fully described our invention, what we claim, and desire tosecure by Letters Patent, is-

l. In a thermostat of the character described, the bed orsupporting-surface A; the vertical flat plate H extending downward fromand sustained by said bed; the weighted bar E normally united to saidplate H by fusible solder and with its thus-united portion setvertically and on a plane parallel with the plate H; a metallic springsupported from the bed and in contact with the opposite end of the barE; and electrical connections conn ecting the said spring and said plateH with the wires of an electrical circuit, substantially as described.

2. ln a thermostat of the character described, the bed orsupporting-surlace A; the plate H secured to said bed a-nd provided withthe downwardly-extending vertical ilat portion H; the Weighted bei' Ehaving the vertical Hat portion of one end united to said plate H byfusible solder, the other end of said bar being provided with a. step oiledge E; the spring' C supported at one end by the bed and with itsother end resting on said step; and electrical connections connectingthe said spring C and plate H with the Wires of au electrical circuit,substantially as set forth.

RICHARD P. OSGOOD. JOHN D. OSGOOD. Witnesses:

A. N. BONNEY, E. A. SUETT.

